Material hardness grading device



Dec. 5, .1961 P. R. GJERTSEN 3,011,334

MATERIAL HARDNESS GRADING DEVICE Filed Oct. 29, 1958 2 Sheets-Sheet 1[NV EN TOR. P R, GJERTSEM.

Dec. 5, 1961 Filed Oct. 29, 1958 P. R. GJERTSEN MATERIAL HARDNESSGRADING DEVICE 2 Sheets-Sheet 2 INVENTOR. PAUL R. GJERTSEM- UnitedStates Patent 3,011,334 MATERIAL HARDNESS GRADING DEVICE Paul R.Gjertsen, 8618 Dearborn Ave., Detroit 17, Mich.

I Filed Oct. 29, 1958, Ser. No. 770,330

6 Claims. 01. 73-7 This invention relates to the grading of the hardnessof materials, and more particularly to a material hardness gradingdevice.

It is an object of the present invention to provide a grading devicewhich determines the hardness of various materials by a wearing action.

It is an object to provide a hardness grading device particularlyadaptable in the field of ceramics as applied to the abrasive industryin connection with grinding wheels,

honing stones, etc.

It is another object to'provide in the grading device, a verticallyslidable head and clamp from which depends a blade of suitable materialof predetermined hardness. The grader also includes a horizontallyreciprocal slide carrying a vise in which the article to be tested issecured, and wherein the vertically adjustable blade bears against anedge of the article during reciprocal movernents thereof. 7

' It is still another object herein to provide a novel form of materialhardness grading device wherein the article to be graded is reciprocatedagainst and transversely of the edge of a blade of known hardness, andwherein the wearing action under a predetermined load for apredetermined number of reciprocations of the article effects a downwardmovement of said blade into the article, a

' measurable distance proportional to its hardness.

These and other objects will be seen from the following specificationand'claims in conjunction with the appended drawing in which:

FIG. 1 is a front elevational view of the present material hardnessgrading machine.

I FIG. 2 is a section taken on line 2-2 of FIG. 1.

FIG. 3 is an elevational view showing a different form of head mounting.

FIG. 4 is a fragmentary plan view thereof.

It will be understood that the above drawings illustrate merelyapreferred embodiment of theinvention and that other embodiments arecontemplated within the scope of the claims hereafter set forth.

Referring to the drawings, the present material hardness grading machineincludes base 11 and projecting'upwardly therefrom column 12 securedthereto byv Welding as at 13.

Forwardly extending top platform 14 is secured adjacent the upper end ofcolumn 12 as by welding at 15; and

spaced therebelow in parallel relation is forwardly ex tending bottomplatform 16 secured to saidcolumn as by welding 17.

A pair'of opposed upright inwardly directed guides 18 are secured toforward edges of plaftorms 14 and 16 as by the welds 19 providing arigid structure. Each of said guides includes an inwardly directedchannel 20 within which is slidably positioned the respective oppositeedge of vertically adjustable head 21.

Counterbalance lever 22 is pivotally mounted intermediate its ends uponpin 23 supported between uprights 24 secured at 25 to top platform 14.The forward end 26 of lever 22 has an upright slot 29 through whichloosely projects threaded stud 27 whose lower end is secured down intohead 21 as at 28, FIG. 1. Nut 30 and lock nut 31 are threaded over theupper end of stud 27 operatively engaging the top of lever 22.

' Control bar 32 is arranged above and is secured to lever 22 inparallel relation, and has mounted thereon the slidably adjustableweight 33, which on adjustment v 3,011,334 Patented Dec. 5, 1961 issuitably secured thereto as by the welds 35, FIG. 1.

Clamp 34 is undercut at 36 to cooperatively receive clamping plate 37which is mounted over the forwardly extending studs 38 carried by clamp34. Plate 37 .is secured thereto by the wing nuts 39, with the elongatedblade 40 interposed between clamp body 34 and clamping plate 37.

Blade 40 is of a suitable predetermined and known abrasive material andhas a predetermined surface roughness on the lower wearing edge thereofadapted for engagement with a workpiece or blade W, the hardness ofwhich is to be graded in the present machine. The hardness of blade 40is known.

Rearwardly extending plate 41 is secured at 41 to head 21 and overliesone side of top platform 14, as shown in FIG. 1. Disc 42 iseccentrically journaled at44 .upon platform 14 at one end thereof andhas an elongated handle 43, whereby rotation thereof in a clockwisedireection, as in FIG. 2, will cause raising of head 21. This isadvantageous in setting up the machine for a grading operation. Lockingarm 45 is pivotally mounted at 46 upon the undersurface of platform 14adjacent handle 43'and may be swung outwardlyin a horizontal plane forsupporting and retaining handle 43 in an elevated head lifting positionso that said discvneed not be retainedmanually.

Mounted below head 21 are opposed pairs of longitu dinally spacedupright supports 47 secured at 48 to base 11, and carrying at theirupper ends the transverse elongated parallel guides 49. These haveinterior opposed grooves 50 slidably receiving horizontal slide, 51. J

Elongated rackgear 52 is secured as by welding to the centralundersurface of slide 51, and is in mesh with pinion 53 on driveshaft 54projecting from electric motor 55. Said motor is mounted on base 11 andis retained thereon by securing strap 56 and holddown bolts 57;

A pair of upright limit switches 58 are mounted upon base 11 spacedoutwardly from supports 47. These carry upwardly projectingrollers 59 inthe form of actuators for said limit switches. These actuators lie inthe hori-. zontal path of movement of" slide 51. Upon engagement of saidslide with one of said actuators, the corresponding limit switch causesa reversal of the drive of'the electric motor 55.Accordingly,'horiz'ontal slide 51 is adapted for continuous reciprocalmovement between limit switch actuators 59, for a predeterminednumber ofreciprocations.

A central upright support 60 projects from and is' secured to,slide 51and carries thereon the upwardly inclined U-shaped vise'61. Said viseincludes pressure screw 62 which operatively engagesclamping plate 63for securing the work or bladeW against the opposing stationary grip ofvise 61, and includeslock nut 64. The blade or article whose hardness isto be graded is of a ceramic or abrasive material and is elongated andrectangular in shape as shown in FIG. 2, for illustration.

The article W extends transversely of the elongated horizontallydisposed test blade 40 of known hardness.

The work W may represent an actual blade or merely the material fromwhich a grinding wheel or honing stone is to be formed. In operation,the head 21 is vertically movable inits guides 18 but in limitedamounts. The slide 51 and the vise mounted work W is horizontallyreciprocal under the drive of reversible motor 55, Vertical head 21 islowered manually on release of arm 45 until blade .40. rests on thearticle W to be tested. Thehorizontal slide is then reciprocated causingthe material tested to be pulled across blade 40.

Horizontal slide 51 has controlled movements in view of the limitswitChes S S and will have a predetermined number of reciprocations.This relative movement will cause the blade 40 under predetermined loadto wear down into the material W, thereby indicating by the depth of thewear its hardness. This downward wear causes a corresponding downwardmovement of slide 21 which is measured by dial indicator 72.

For this purpose, upright support 65 is'mounted upon the top of head 21upon one side thereof and is interiorly threaded t-o adjustably receivetherein headed screw 66. Elongated upwardly inclined arm 67 has adownturned end 68 pivotally connected as 69 to the upright extension 70upon one side of column 12, as shown in the drawings.

Arm 67 at itsupper end terminates in the upright 71 to which is secureddial indicator 72 by fasteners 73. Said indicatorincludes the usual dial74 and movable pointer 75 for indicating the amount of vertical movementof plunger 76 which depends therefrom in a conventional manner. At thebeginning of the operation plunger 76 restsupon headed screw 66 as shownin FIG. 1, and the indicator pointer 75 is set to zero. The pivotalmounting 69 of indicator support arm 67 is sufficiently tight so thatarm 67 is self supporting, and plunger 76 responds to downward verticalmovement of screw 66 on head 21 to thereby give a visual indication ondial 74 of the extent of downward wearing movement of blade 4%- into thework W at the point of contact 78, shown in FIG. 1. Arm 67 rests on stp79.

V Stop arm 77 is secured across the top of extension 70 and projectsinwardly thereofwhereby the dial Supporting arm 67 may be swung in aclockwise direction when not in use, being limitedin its movement bystop 77.

Accordingly, dial indicator 72 will provide direct readings of the exactdepth of wear into the article being tested, thereby iudicatingitshardness in accordance with predetermined standards. Since the weight ofthe vertical head 21 is what exerts the downward pressure of blade 4%,and'since the pressure on the blade has a direct effect on its Wearingquality with respect to the work, said vertical head is equipped withthe adjustable counterweight22-33 above described.

In thismanner, the blade 40- may be given such pressure as is bestsuited to. the article being tested. It has been established that thesurface roughness of the lower edge of blade 40 has a very definiteeffect on its wear into the article tested. Therefore blade .40 shouldbe used only once, and thereafter resurfaced to a standard degree ofconventional roughness.

This is done by pulling the cutting edge of blade 46 across the face ofa diamond impregnated cup wheel or similar device each time the blade isused. It has been found extremely important that the stones used in themanufacture of grinding wheels, honing stones or the like be graded fordetermining their exact hardness, since the use of ungraded stones ofunknown hardness will result in a large number of rejects for a givenhoning or grinding operation.

The following data shows the importance of employing stones of knownhardness. Hereunder is a copy of a report on tests conducted by theBower Roller Bearing Co., of Michigan, and wherein variably gradedstones were used. The articles honed were rollers for roller bearings /8inch in diameter by /2 inch length and under Since ungraded stones couldresult in any of the above cordingly FIGS. 3 and 4 illustrate a slightlydifferent form of head mounting designed to minimize friction.

instead of opposed upright guides 18 shown in FIGS. 1 and 2, there ismounted forwardly of platforms 1'416, the upright mounting plate 80suitably secured thereto as by welding, similar to the welds 19 in FIG.2. Said plate on its opposite sides includes upright edges 81 and thecentral upright key 82.

Opposed spaced uprights 83 are arranged upon and against opposite sidesof mounting plate 8t and have corresponding internal grooves tocooperatively receive keys 82. Said uprights are secured to platesfiby aseries of spaced fasteners 84.

Uprights 83 extend forwardly of plate 80' and have formed therein theopposed inwardly directed upright grooves 85. Vertically adjustable head21' is positioned between uprights 83 in spaced relation and includes inits outer upright edges the outwardly directed grooves 86 in opposedregistry with grooves 85 respectively. Vertically spaced upright rollers87 are interposed between head 21 and uprights 83 and movably nestedwithin the respective grooves 35 and 86 for guidably positioning head21, and for facilitating its vertical adjustments with a minimum offriction.

Studs 88 are secured upon opposite sides of head 21 and projectlaterally thereof to extend'supportably below the respective rollers 87for maintaining the same against vertical displacement relative to head21. Said head terminates in clamp plate 34 secured thereto at 35', beingrecessed at 36' to receive a blade, like blade 40 of FIG. 1.

At least one upright side of mounting plate 80 is ground on an angle ofapproximately one-half of one degree so as to extend upwardly andinwardly. Upright 83 is vertically adjustable relative to said taperedsurface. Accordingly, any such vertical adjustment relative to mountingplate 80 brings said upright closer to the other upright resulting in apreloading' of rollers 87 to any desired amount. j Having described myinvention, reference should now be had to the following claims.

I claim:

1. In a material hardness grader, a platform base, an upright columnthereon, a framework securedto and pro-, jecting forwardly of saidcolumn above said base, an upright vertically movable head guidablymounted upon said framework, a clamp at the lower end of said head, ahorizontally disposed abrasive blade of predetermined hardness securedin said clamp parallel to said column, a horizontally reciprocal slidemounted on said base below said 1 head, movable lengthwise of saidblade, means'to reciprocate said slide, a vise secured upon said slideadapted to suuportedly mount an abrasive material of unknown. hardness,said vise so mounted as to position said material transversely below andagainst the undersurface of said blade, said blade resting upon saidmaterial and wearing down thereinto at one point along its length aftera predetermined number of reciprocations of said slide "and material tobe tested along the length of the blade, effecting correspondingdownward movement of said head, and an indicator mounted on saidframework having a vertically movable plunger engageable with andresponsive to vertical movements of said head, the extent of suchvertical movement indicating the degree of hardness of said material inaccordance with predetermined standards, the arrangement of relativemovement between the material tested and the testing blade providing fora series of limited cuts into the Work at points throughout its lengthto test for uniformity of hardness.

2. In the hardness grader of claim 1, a counterbalance for said head toregulate its downward thrust, consisting of a lever pivotally mountedintermediate its ends upon said framework above said head, at rightangles thereto and at its forward end connected to said head, a load support joined to the other end of said lever extending above and parallelthereto, and a weight slidably mounted on said load support.

3. In the hardness grader of claim 1, the mounting of said indicatorincluding an upwardly and forwardly inclined bracket arm secured at itslower end to said column, said arm including the upright extension towhich said indicator is secured in vertical alignment with said head,said arm being swingable upwardly, and transverse stops retaininglyengaging said arm respectively in use and in raised position.

4. In the hardness grader of claim 1, a horizontal lift arm secured tosaid head and extending rearwardly above said framework, an uprightmanually rotatable disc eccentrically journaled upon the side offramework normally spaced below said arm and upon rotation adapted tocam against and lift said arm and head relative to said framework, ahandle on said disc, and a lock arm pivotally mounted on said frameworkhorizontally swingable to supportably engage said handle in headelevating position.

5. In the hardness grader of claim 1, the mounting of said head uponsaid framework including a pair of spaced uprights secured to saidframework and having therein head opposing said first groovesrespectively, vertically spaced rollers loosely positioned within theopposed grooves on opposite sides of said head guidably engaging saidhead, and an upright mounting plate supportedly securing said uprights,at least one of its sides engaged by an upright being inclined upwardlyand inwardly, vertical adjustment of at least one of said uprightsbringing the same closer to the outer upright for preloading saidrollers.

References Cited in the file of this patent UNITED STATES PATENTS1,824,483 Hubmann et al. Sept. 22, 1931 2,093,650 Sunnen Sept. 21, 19372,175,173 Batohelder Oct. 10, 1939 2,330,578 Harris Sept. 28, 19432,335,235 Clifton Nov. 30, 1943 2,376,155 Kratzer May 15, 1945 2,662,397Goldberg et a1 Dec. 15, 1953

